"Die Hard" celebrated its 35th anniversary this month. Since its release, behind-the-scenes secrets about the film have emerged over the years. 

The 1998 action film helped boost Bruce Willis' career, but the 68-year-old actor was reportedly the last choice for the starring role. 

Arnold Schwarzenegger gave Willis a piece of advice after the actor decided to venture into Schwarzenegger's territory of action films.

And an off-camera joke Willis cracked ultimately made its way to the final cut of the film and is now considered one of the most famous lines from the '80s movie.

Bruce Willis Die Hard

Bruce Willis rose to fame with his role in "Die Hard." (Getty Images)

ON THIS DAY IN HISTORY, JULY 15, 1988, ‘DIE HARD’ HITS THEATERS, FIRST IN THE FRANCHISE

Directed by John McTiernan, "Die Hard" stars Willis as an NYPD officer, John McClane, who unexpectedly finds himself fighting to save his estranged wife, Holly Gennaro McClane (Bonnie Bedelia) and her co-workers after they are taken hostage by a band of terrorists led by Hans Gruber (Alan Rickman) during an office Christmas party at the Los Angeles skyscraper Nakatomi Plaza Christmas Eve.

Willis' wife, Emma Heming, recently took to Instagram to share how "proud" she is about her husband's role in the film.

"Back in 2018 (when these videos and pictures were taken) we took Mabel and Evelyn to the Fox lot to peek at the archives as well as see the larger-than-life mural of their dad," Heming began her caption. 

APP USERS CLICK HERE TO SEE INSTAGRAM POST

"This mural was unveiled in front of Bruce back in 2013 to commemorate Die Hard’s 25th anniversary. Today marks Die Hard’s 35th anniversary when it hit the screens and the rest is history. What Bruce has been able to accomplish in his career will never be lost on us. We are so proud of him."

Included in Heming's post were videos of his two youngest daughters, Mabel, 10 and Evelyn, 8, holding their dad's hand as they made their way through the FOX lot, looking through "Die Hard" archives.

Bruce Willis and his wife Emma Hemming Willis at the roast of Bruce Willis

Willis' wife, Emma Heming, recently took to Instagram to share how "proud" she is of her husband's role in the film. (Frederick M. Brown/Getty Images)

In celebration of "Die Hard" turning 35, here's a look at a few secrets about the film. 

Schwarzenegger said Willis wouldn't make it in action movies

According to a new book, "The Last Action Heroes: The Triumphs, Flops, and Feuds of Hollywood’s Kings of Carnage," Schwarzenegger passed on the role as John McClane but had a few things to say to Willis after Willis took on the role.

BRUCE WILLIS’ 'DIE HARD' TURNS 35: HOW CHRISTMAS MOVIE DEBATE FIRST STARTED

Author Nick de Semlyen wrote in his book the former governor of California saw Willis out at dinner in Santa Monica shortly after the film's debut. Schwarzenegger was already dining at the Ivy by the Shore when Willis entered the upscale eatery and took a seat at a table on the other side of the restaurant. 

Arnold Schwarzenegger and Bruce Willis

Arnold Schwarzenegger told Bruce Willis he wouldn't be an action movie star because of his "toothpick arms." (Kypros)

"Know why you’ll never be an action star?" Schwarzenegger called out to Willis across the room, loud enough that everyone in the restaurant could hear, according to de Semlyen. 

"No, Arnold, why?" Willis replied. 

Schwarzenegger then flexed his biceps, pointed to his arm and announced in his thick Austrian accent, "Toothpick arms."

"Die Hard" became the highest-grossing action film in 1988 and was the beginning of Willis' long, successful career in show business.

Willis suffers from ‘partial hearing loss’ due to an on-set accident

Following the film's success, Willis did an interview with Oprah Winfrey and shared that he liked to perform a lot of his own stunts, which had its downfall.

"This part was a lot harder than just about anything I’ve done for a lot of reasons," Willis said. 

Bonnie Bedelia and Bruce Willis in Die Hard

Bonnie Bedelia is held down by Bruce Willis in a scene from "Die Hard." (Getty Images)

"If you saw the film, they really kind of beat me up in this thing. It’s a very physical part. I did a lot of my own stunts in it."

In 2007, Willis told The Guardian that because he enjoyed the dangerous scenes in "Die Hard," he suffers from partial hearing loss.

"Due to an accident on the first ‘Die Hard,' I suffer two-thirds partial hearing loss in my left ear and have a tendency to say, 'Whaaa?'" Willis said at the time.

Willis shot a gun a little too close to his ear during a scene for "Die Hard," which led to the partial hearing loss, his daughter Rumer later revealed in an interview with the Toronto Sun.

John McClane almost went to Frank Sinatra

The lead role in "Die Hard," John McClane, almost looked entirely different.

According to Business Insider, the film was based on the book "Nothing Lasts Forever" by Roderick Thorp. The book is a sequel to Thorp's novel, "The Detective," which was made into a movie by the same name in 1968.

Frank Sinatra

The lead role in "Die Hard" reportedly almost went to Frank Sinatra. (Warner Brothers/Getty Images)

Sinatra played the lead role, Detective Joe Leland, in the film.

The outlet reported that since "Die Hard" was a sequel, the production team was "contractually obligated" to offer the lead role to Sinatra.

He was 73 years old at the time of the offer and turned down the opportunity, the outlet reported.

The outlet also reported that Schwarzenegger was next in line to receive the offer. The "Terminator" star turned down the opportunity – along with multiple other Hollywood stars — leading Willis straight to the leading role.

The late Alan Rickman hated guns

Alan Rickman's first film role was in "Die Hard," and he was not fond of the idea of an action movie.

"I read it, and I said, ‘What the hell is this? I’m not doing an action movie,’" Rickman said in 2015, according to The Hollywood Reporter. "Agents and people said, 'Alan, you don’t understand, this doesn’t happen. You’ve only been in LA two days, and you’ve been asked to do this film.'"

Alan Rickman

The late Alan Rickman was hesitant about starring in an action movie. (Mike Marsland)

At the time, the "Harry Potter" actor admitted he was afraid of the scenes that required his character, Hans Gruber, to shoot a gun. 

"If you look carefully, you’ll see me blinking," he said at the time. "It is shocking how thrilling it is to shoot a machine gun, that I discovered."

Rickman, who skyrocketed to international fame after starring in the "Harry Potter" franchise as Professor Severus Snape, died in 2016 after a battle with cancer. 

Willis received $5 million for the role

In the '80s, "Die Hard" seemed impossible to cast, with Hollywood heavy hitters like Schwarzenegger, Clint Eastwood, Richard Gere and others passing on the role as NYPD Det. McClane.

‘DIE HARD’ STAR BRUCE WILLIS NEARLY DIED DURING FIRST DAY OF FILMING: BOOK

Willis was not the team's first, even second or third choice for the role. Willis' agent, Arnold Rifkin, took full advantage of the opportunity, hiking up the actor's acting price to $5 million, according to author de Semylen.

"All the possible action people turned it down," producer Larry Gordon said, per de Semlyen. "We had a good script, but we could not get anybody to play John McClane."

movie poster of Die Hard

Bruce Willis received $5 million for the role. (Win McNamee/Getty Images)

Rifkin was aware of the trouble the "Die Hard" team was going through and told Gordon, "Take it or leave it. If you don’t close the deal by Friday, he’s gonna go to Japan and do some commercials."

BRUCE WILLIS JOINED BY DEMI MOORE, EMMA HEMING AND FIVE DAUGHTERS FOR FIRST BIRTHDAY AFTER DEMENTIA DIAGNOSIS

Willis initially was like the others and passed on the role because of his commitment to the TV hit "Moonlighting." His co-star, Cybill Shepherd, announced her pregnancy shortly after he passed on the role, which gave him an 11-week window of availability.

"They’re going to laugh you off the screen," Glenn Gordon Caron, the creator of "Moonlighting," told Willis when he was cast. "That’s a Schwarzenegger movie." 

Willis eventually locked in the $5 million deal, an unheard of salary for an actor getting started in his career in the late '80s, according to de Semlyen's book. 

Demi Moore and Willis tied the knot three weeks into filming

Moore and Willis were feeling spontaneous at the beginning of "Die Hard's" production. 

Four months into their relationship, the couple tied the knot at the Golden Nugget Hotel in Las Vegas in 1987. In her memoir, "Inside Out," Moore revealed that saying "I do" was completely unplanned.

Bruce Willis and his ex wife

Bruce and Demi Moore were married for 12 years before splitting in 2000. (George Rose via Getty Images)

"We were moving to the gambling tables when Bruce said, 'I think we should get married.' We'd been joking about it on the flight there, but suddenly it didn't seem like he was kidding," Moore wrote, according to People magazine.

CLICK HERE TO SIGN UP FOR THE ENTERTAINMENT NEWSLETTER

The following month, the couple had a wedding for family and friends that was officiated by musician Little Richard. 

Willis and Moore have stayed close after their divorce in 2000. The couple share three daughters — Rumer, Scout and Tallulah.

Willis' famous ‘Yippee-ki-yay’ line was not planned

Perhaps the most famous line in "Die Hard" originated as a joke Willis told on set of the film. 

Bruce Willis smiles on the red carpet wearing a black suit, white button down and blue patterned tie

Bruce Willis' iconic line in "Die Hard" started out as a joke. (Tolga Akmen/AFP )

In a 2013 interview with Ryan Seacrest, Willis admitted he was just cracking jokes with the crew members when he said, "Yippee-ki-yay, motherf-----!"

CLICK HERE TO GET THE FOX NEWS APP

"It was a throwaway," Willis said at the time. "I was just trying to crack up the crew, and I never thought it was going to be allowed to stay in the film."

Willis' role in "Die Hard" as officer McClane took him to super stardom in 1988 and spurred multiple sequels. Since then, his four-decade career has amassed more than $5 billion in box office sales worldwide.

Willis has largely stayed out of the spotlight since it was revealed in March 2022 he was retiring from acting due to an aphasia diagnosis. He has since been diagnosed with frontotemporal dementia.